/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

:root {
    /* 浅色主题 */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --border-color: #e5e7eb;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-hover: rgba(0, 0, 0, 0.15);
    --accent: #4f46e5;
    --accent-hover: #7c3aed;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
}

[data-theme="dark"] {
    /* 深色主题 */
    --bg-primary: #1f2937;
    --bg-secondary: #111827;
    --text-primary: #f9fafb;
    --text-secondary: #d1d5db;
    --text-muted: #9ca3af;
    --border-color: #374151;
    --shadow: rgba(0, 0, 0, 0.3);
    --shadow-hover: rgba(0, 0, 0, 0.4);
    --accent: #6366f1;
    --accent-hover: #8b5cf6;
    --success: #34d399;
    --warning: #fbbf24;
    --error: #f87171;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* 加载动画 */
body:not(.loaded) {
    opacity: 0;
    transition: opacity 0.5s ease;
}

body.loaded {
    opacity: 1;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 导航栏样式 */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    transition: all 0.3s ease;
    border-bottom: 1px solid var(--border-color);
}

[data-theme="dark"] .navbar {
    background: rgba(31, 41, 55, 0.95);
    border-bottom: 1px solid var(--border-color);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo a {
    font-size: 1.5rem;
    font-weight: 700;
    color: #4f46e5;
    text-decoration: none;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    color: #333;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: #4f46e5;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: #4f46e5;
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 100%;
}

.nav-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
}

.theme-toggle:hover {
    background: var(--bg-secondary);
    transform: scale(1.1);
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background: #333;
    margin: 3px 0;
    transition: 0.3s;
}

/* 首页样式 */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="1" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.3;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
    z-index: 1;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.highlight {
    color: #fbbf24;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 500;
    margin-bottom: 1.5rem;
    opacity: 0.9;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    opacity: 0.8;
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 12px 30px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    display: inline-block;
    border: 2px solid transparent;
}

.btn-primary {
    background: #fbbf24;
    color: #1f2937;
}

.btn-primary:hover {
    background: #f59e0b;
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(251, 191, 36, 0.3);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: #4f46e5;
    transform: translateY(-2px);
}

.profile-card {
    position: relative;
    width: 300px;
    height: 300px;
    margin: 0 auto;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease;
}

.profile-card:hover {
    transform: scale(1.05);
}

.profile-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.profile-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(transparent, rgba(0, 0, 0, 0.8));
    padding: 2rem 1rem 1rem;
    transform: translateY(100%);
    transition: transform 0.3s ease;
}

.profile-card:hover .profile-overlay {
    transform: translateY(0);
}

.social-links {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.social-link {
    color: white;
    font-size: 1.5rem;
    transition: color 0.3s ease;
}

.social-link:hover {
    color: #fbbf24;
}

/* 通用部分样式 */
.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: #1f2937;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: #4f46e5;
    border-radius: 2px;
}

/* 关于我部分 */
.about {
    padding: 100px 0;
    background: #f8fafc;
}

.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 4rem;
    align-items: start;
}

.about-text p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    color: #4b5563;
    line-height: 1.7;
}

.education {
    margin-top: 2rem;
}

.education-item {
    background: white;
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    margin-bottom: 1rem;
}

.education-item h4 {
    font-size: 1.2rem;
    color: #1f2937;
    margin-bottom: 0.5rem;
}

.education-item p {
    color: #6b7280;
    margin-bottom: 0.5rem;
}

.skills {
    margin-top: 2rem;
}

.skills h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.skill-tag {
    background: #4f46e5;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 25px;
    font-size: 0.9rem;
    font-weight: 500;
}

.about-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.stat-item {
    text-align: center;
    padding: 2rem;
    background: white;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease;
}

.stat-item:hover {
    transform: translateY(-5px);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: #4f46e5;
    margin-bottom: 0.5rem;
}

.stat-label {
    color: #6b7280;
    font-weight: 500;
}

/* 研究部分 */
.research {
    padding: 100px 0;
    background: white;
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.research-card {
    background: white;
    padding: 2.5rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid #e5e7eb;
}

.research-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.research-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #4f46e5, #7c3aed);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    color: white;
    font-size: 2rem;
}

.research-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #1f2937;
}

.research-card p {
    color: #6b7280;
    line-height: 1.6;
}

/* 发表论文部分 */
.publications {
    padding: 100px 0;
    background: #f8fafc;
}

/* 项目展示部分 */
.projects {
    padding: 100px 0;
    background: white;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.project-card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    border: 1px solid #e5e7eb;
}

.project-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.project-image {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.project-card:hover .project-image img {
    transform: scale(1.1);
}

.project-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.project-card:hover .project-overlay {
    opacity: 1;
}

.project-link {
    width: 50px;
    height: 50px;
    background: #4f46e5;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    text-decoration: none;
    font-size: 1.2rem;
    transition: all 0.3s ease;
}

.project-link:hover {
    background: #7c3aed;
    transform: scale(1.1);
}

.project-content {
    padding: 1.5rem;
}

.project-content h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: #1f2937;
}

.project-content p {
    color: #6b7280;
    line-height: 1.6;
    margin-bottom: 1rem;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.tech-tag {
    background: #e5e7eb;
    color: #374151;
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 500;
}

.project-stats {
    display: flex;
    gap: 1rem;
    font-size: 0.9rem;
    color: #6b7280;
}

.project-stats span {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.publications-list {
    max-width: 800px;
    margin: 0 auto;
}

.publication-item {
    display: flex;
    gap: 2rem;
    margin-bottom: 3rem;
    padding: 2rem;
    background: white;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease;
}

.publication-item:hover {
    transform: translateY(-5px);
}

.publication-year {
    background: #4f46e5;
    color: white;
    padding: 1rem;
    border-radius: 10px;
    font-weight: 700;
    font-size: 1.2rem;
    height: fit-content;
    min-width: 80px;
    text-align: center;
}

.publication-content h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: #1f2937;
    line-height: 1.4;
}

.publication-authors {
    color: #4f46e5;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.publication-venue {
    color: #6b7280;
    font-style: italic;
    margin-bottom: 1rem;
}

.publication-links {
    display: flex;
    gap: 1rem;
}

.publication-link {
    color: #4f46e5;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.publication-link:hover {
    color: #7c3aed;
}

/* 证书展示部分 */
.certificates {
    padding: 100px 0;
    background: white;
}

.certificates-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.certificate-item {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    border: 1px solid #e5e7eb;
}

.certificate-item:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.certificate-image {
    height: 200px;
    overflow: hidden;
    position: relative;
}

.certificate-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.certificate-item:hover .certificate-image img {
    transform: scale(1.05);
}

.certificate-content {
    padding: 1.5rem;
    text-align: center;
}

.certificate-content h3 {
    font-size: 1.1rem;
    color: #1f2937;
    margin-bottom: 0.5rem;
    line-height: 1.4;
}

.certificate-content p {
    color: #6b7280;
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.certificate-year {
    background: #4f46e5;
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* 工作经历部分 */
.experience {
    padding: 100px 0;
    background: #f8fafc;
}

.experience-section {
    margin-bottom: 3rem;
}

.section-subtitle {
    font-size: 1.8rem;
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 2rem;
    text-align: center;
}

.experience-timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.experience-timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 2px;
    background: #4f46e5;
    transform: translateX(-50%);
}

.timeline-item {
    display: flex;
    margin-bottom: 3rem;
    position: relative;
}

.timeline-item:nth-child(odd) {
    flex-direction: row;
}

.timeline-item:nth-child(even) {
    flex-direction: row-reverse;
}

.timeline-date {
    flex: 0 0 200px;
    text-align: center;
    padding: 1rem;
    background: #4f46e5;
    color: white;
    border-radius: 10px;
    font-weight: 600;
    position: relative;
    z-index: 2;
}

.timeline-item:nth-child(odd) .timeline-date {
    margin-right: 2rem;
}

.timeline-item:nth-child(even) .timeline-date {
    margin-left: 2rem;
}

.timeline-content {
    flex: 1;
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    position: relative;
}

.timeline-content h4 {
    font-size: 1.3rem;
    color: #1f2937;
    margin-bottom: 1rem;
}

.timeline-content ul {
    list-style: none;
    padding: 0;
}

.timeline-content li {
    padding: 0.5rem 0;
    color: #6b7280;
    position: relative;
    padding-left: 1.5rem;
}

.timeline-content li::before {
    content: '•';
    color: #4f46e5;
    font-weight: bold;
    position: absolute;
    left: 0;
}

.awards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.award-item {
    background: white;
    padding: 1.5rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    text-align: center;
    transition: transform 0.3s ease;
}

.award-item:hover {
    transform: translateY(-5px);
}

.award-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, #4f46e5, #7c3aed);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 0.8rem;
    color: white;
    font-size: 1.2rem;
}

.award-content h4 {
    font-size: 1rem;
    color: #1f2937;
    margin-bottom: 0.5rem;
    line-height: 1.3;
}

.award-content p {
    color: #6b7280;
    margin-bottom: 1rem;
}

.award-year {
    background: #4f46e5;
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
    font-size: 0.9rem;
    font-weight: 500;
}

.campus-activity {
    background: white;
    padding: 2rem;
    border-radius: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    max-width: 800px;
    margin: 0 auto;
}

.campus-activity h4 {
    font-size: 1.3rem;
    color: #1f2937;
    margin-bottom: 1rem;
}

.campus-activity ul {
    list-style: none;
    padding: 0;
}

.campus-activity li {
    padding: 0.5rem 0;
    color: #6b7280;
    position: relative;
    padding-left: 1.5rem;
}

.campus-activity li::before {
    content: '•';
    color: #4f46e5;
    font-weight: bold;
    position: absolute;
    left: 0;
}

/* 联系方式部分 */
.contact {
    padding: 100px 0;
    background: white;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
}

.contact-item {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    align-items: flex-start;
}

.contact-icon {
    width: 50px;
    height: 50px;
    background: #4f46e5;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.contact-details h3 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: #1f2937;
}

.contact-details p {
    color: #6b7280;
    line-height: 1.6;
}

.contact-form {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 15px;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 1rem;
    border: 2px solid #e5e7eb;
    border-radius: 10px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #4f46e5;
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* 页脚 */
.footer {
    background: #1f2937;
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-links {
    display: flex;
    gap: 1rem;
}

.footer-links a {
    color: white;
    font-size: 1.5rem;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: #fbbf24;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 2rem 0;
        z-index: 999;
    }

    .nav-menu.active {
        left: 0;
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .about-stats {
        grid-template-columns: 1fr 1fr;
    }

    .contact-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .publication-item {
        flex-direction: column;
        gap: 1rem;
    }

    .publication-year {
        align-self: flex-start;
    }

    .footer-content {
        flex-direction: column;
        gap: 1rem;
    }

    /* 工作经历响应式 */
    .experience-timeline::before {
        left: 20px;
    }

    .timeline-item {
        flex-direction: column !important;
        padding-left: 50px;
    }

    .timeline-date {
        flex: none;
        width: 120px;
        margin: 0 0 1rem 0 !important;
        font-size: 0.9rem;
    }

    .timeline-content {
        margin-left: 0;
    }

    .awards-grid {
        grid-template-columns: 1fr;
    }

    /* 证书展示响应式 */
    .certificates-grid {
        grid-template-columns: 1fr;
    }

    /* 改进的移动端导航 */
    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }

    .hamburger.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .hamburger.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    /* 移动端优化 */
    .profile-card {
        width: 250px;
        height: 250px;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
        gap: 1rem;
    }

    .btn {
        width: 200px;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .about-stats {
        grid-template-columns: 1fr;
    }

    .research-grid {
        grid-template-columns: 1fr;
    }
}

/* 动画效果 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: #4f46e5;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #7c3aed;
}

/* 新增样式 */
.image-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    background: #f3f4f6;
    color: #6b7280;
    font-size: 0.9rem;
}

.image-placeholder i {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    opacity: 0.5;
}

/* 导航链接激活状态 */
.nav-link.active {
    color: #4f46e5;
}

.nav-link.active::after {
    width: 100%;
}

/* 改进的按钮样式 */
.btn {
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

/* 改进的卡片悬停效果 */
.research-card, .publication-item, .stat-item, .certificate-item, .project-card {
    position: relative;
    overflow: hidden;
}

.research-card::before, .publication-item::before, .stat-item::before, .certificate-item::before, .project-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.1), rgba(124, 58, 237, 0.1));
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: 1;
}

.research-card:hover::before, .publication-item:hover::before, .stat-item:hover::before, .certificate-item:hover::before, .project-card:hover::before {
    opacity: 1;
}

.research-card > *, .publication-item > *, .stat-item > *, .certificate-item > *, .project-card > * {
    position: relative;
    z-index: 2;
}

/* 改进的加载状态 */
.loading {
    opacity: 0.7;
    pointer-events: none;
}

/* 改进的响应式设计 */
@media (max-width: 1024px) {
    .hero-title {
        font-size: 3rem;
    }
    
    .section-title {
        font-size: 2.2rem;
    }
    
    .research-grid {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    }
}

@media (max-width: 640px) {
    .hero-title {
        font-size: 2.2rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
    
    .nav-container {
        padding: 0 15px;
    }
    
    .container {
        padding: 0 15px;
    }
}

/* 打印样式 */
@media print {
    .navbar, .hamburger, .back-to-top, .contact-form {
        display: none !important;
    }
    
    .hero {
        background: none !important;
        color: #000 !important;
    }
    
    .section-title::after {
        display: none;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
    }
}
